Pressure from shoppers has boosted the volume of organic UK produce in supermarkets, a consumer group claims.
Proponents say there are health benefits to organic food
The Soil Association's survey of eight food chains revealed the proportion of imported organic produce dropped to 18% from 24% the previous year.
The findings are based on research conducted by 1,484 volunteers.
Peter Melchett, of Soil Association, said most supermarkets sourced more seasonal, UK-produced organic food "thanks to persistent public scrutiny".
He said: "Our survey shows that positive consumer pressure pays off.
"Most, but not all, of the major supermarkets have raised their game in sourcing more seasonal, UK-produced organic food."
Mr Melchett, the consumer group's policy director, said the increased range of UK organic produce on supermarket shelves would benefit shoppers, farmers and the environment.
The survey named Waitrose and Marks & Spencer as the two retailers which source the greatest proportion of organic produce from UK farmers.
And chicken was found to be the organic item most likely to be sourced from the UK, while organic apples are most frequently imported.
The survey results are based on the work of 1,484 volunteers who scanned supermarket shelves for eight seasonal UK organic foods during November and December 2005.
Those items were potatoes, apples, carrots, onions, pork, beef, chicken and lamb.
The volunteers found that 89% of these organic items sold at Waitrose and M&S were from the UK.
This figure compared to 86% at Sainsbury's, 78% at Tesco, 76% at the Co-op, 70% at Somerfield, 69% at Asda and 61% at Morrisons.
Just 40% of organic apples across all eight chains were from the UK.
However, this was up from 24% the previous year.
And the volume of organic onions from the UK increased from 55% to 73% in that time.
Potatoes were the only item that underwent a dip, falling from 93% to 90%.
The Soil Association praised Tesco for sourcing more organic beef and pork from the UK rather than from overseas producers in countries such as Argentina.